Just War, Terrorism, and Empire

Bearing Blog as an post up asking interesting and difficult questions about the nature of just war as regards a diffused threat such as terrorism.

I've sometimes wondered if one of the difficulties in applying just war doctrine to some of our current problems is that our thinking on just war was mostly developed during the medieval period, when there was indeed a "community of nations", all based on at least somewhat similar principles, in Europe.

In some ways, our current situation seems to me vaguely like that which faced Rome in the period from 100BC to 30AD. Picture America as late republican through early imperial Rome. A large, wealthy country, only recently (last century) a major player on the world stage. Very proud of its middle class family virtues and republican form of government -- despite the fact that the ruling elite has almost entirely abandoned those ideals.

Picture Europe as the aging Helenistic world of the same era: Old, cultured, tremendously proud of its intellectual and cultural heritage, and yet producing few thinkers or artists of the level of those who came several hundred years before, demographically imploding, morally corrupt, politically Byzantine and militarily powerless.

Now, Rome felt it to be a necessity for security and stability that it begin to take possession of outlying, unstable countries and put in place stable, friendly governments there. Later, as their innate distrust of empire wore away and was replaced with an increasing need for funds and citizens, they simply started annexing outlying countries.

And, of course, there were the 'barbarian' tribes and countries outside the Roman sphere of influence. During certain periods they and the Romans pretty much left each other alone. But as they became dangerous and unstable the Romans felt that security necessitated that they fight a series of low level defensive and offensive actions -- either conquering or driving back various tribes.

How does just war doctrine deal with such a situation? Should the western world simply try to keep the 'barbarian' hordes out? Does it try to set up stable client states to keep the natives under control. (Our record there certainly isn't good.) Does it do its best to police the unstable countries at its periphery and hope that eventually cultural conquest will achieve what military conquest cannot?